CONTENTS
Introduction = 1
1. A Modern Theory of Customary International Law = 11
2. The Factual Framework：Codification in Past and Present = 63
3. Codification and Progressive Development of International Law (jus scriptum) = 93
4. Methods of Codification：Codes, Resolutions and Conventions = 117
5. Effects of a Convention on Pre-existing Customary International Law = 149
6. Generation of New Customary International Law = 167
7. Modification of Conventional Rules by Subsequent Customary Law = 193
8. Identification of the Declaratory Quality of Conventional Rules = 225
9. Effects of the Declaratory Nature of Conventional Rules = 249
Conclusions = 275
OVERVIEW = ⅶ
ABBREVIATIONS = xix
FOREWORD TO THE SECOND EDITION = xxiii
INTRODUCTION = 1
A. Outline, Approach and Possible Significance of the Present Study = 3
B. Delimitations = 6
1. A MODERN THEORY OF CUSTOMARY INTERNATIONAL LAW = 11
A. Introduction = 15
B. What Constitutes State Practice? = 16
Ⅰ. In General = 16
Ⅱ. The Value of Statements = 17
a) Restrictive Views = 17
b) Safeguards = 19
c) Verbal Acts as State Practice = 19
Ⅲ. Functions and Examples = 23
a) Functions = 23
b) Votes = 23
c) Consensus = 24
d) Package Deals = 25
e) Collective Stands = 25
Ⅳ. Written Texts (Conventions etc.) as State Practice? = 25
Ⅴ. State Practice qua Contractual Obligation = 26
C. The Material Requirements of Customary Law = 29
Ⅰ. General Practice：Notion and Implications = 29
Ⅱ. The Practice of "Specially Affected" States = 30
Ⅲ. The Practice of Dissenting States = 33
a) Persistent Objectors = 33
b) Subsequent Objectors = 36
Ⅳ. Passive Conduct = 37
a) The Traditional View = 37
b) The Voluntarist Approach = 41
Ⅴ. Uniformity and Consistency of Practice = 42
Ⅵ. Duration of Practice = 45
D. Opinio juris = 47
Ⅰ. Concept = 47
Ⅱ. Evidence of Opinio juris = 50
Ⅲ"Instant" Customary Law = 52
Ⅳ. Formation of Customary Law = 53
E. Desuetude and Modification of a Customary Rule = 55
F. Special Customary Law = 56
G. Customary Law and the Hierarchy of Sources = 57
Ⅰ. Hierarchy of Sources = 57
Ⅱ. Conflicts between Rules of Different Sources = 59
H. Conclusions = 60
2. THE FACTUAL FRAMEWORK：CODIFICATION IN PAST AND PRESENT = 63
A. Efforts Individuals and Private Organizations = 65
Ⅰ. Individual Efforts = 65
Ⅱ. Private Organizations = 66
B. Official Efforts Outside the United Nations = 67
Ⅰ. 1815-1914 = 67
Ⅱ. The League of Nations (1919-1946) = 69
a) The 1930 Hague Conference - Preparation and Outcome = 69
b) Reasons for Failure = 71
Ⅲ. Codification in the Inter-American System = 72
Ⅳ. Other Official Bodies = 73
C. The UN International Law Commission (ILC) = 74
Ⅰ. Establishment = 74
Ⅱ. Election and Composition = 75
Ⅲ. Functions = 76
Ⅳ. Selection of Topics = 76
Ⅴ. Procedure = 78
Ⅵ. Accomplishment of Work = 80
Ⅶ. Relationship with States and the Sixth Committee = 82
a) Direct Relations with States = 82
b) Sixth Committee = 82
Ⅷ. Example：The 1969 Vienna Convention on the Law of Treaties = 84
Ⅸ. Appreciation = 84
a) The ILC as a "Quasi-legislative Body" = 84
b) Quantitive Appreciation：How Effective is the ILC? = 85
c) Selection of Topics = 87
D. Other UN Bodies = 89
3. CODIFICATION AND PROGRESSIVE DEVELOPMENT OF INTERNATIONAL LAW (JUS SCRIPTUM) = 93
A. The UN Framework = 95
Ⅰ. Article 13 subpara. 1(a) of the UN Charter = 95
Ⅱ. Response to Article 13 subpara. 1(a) = 96
a) The Committee on the Progressive Development of International Law and its Codification (1946／47) = 96
b) The ILC-Statute and the Practice of the ILC = 98
c) Doctrine = 100
B. The Concepts of Codification and Progressive Development = 102
Ⅰ. Codification = 102
Ⅱ. Progressive Development = 105
Ⅲ. "Agreement" and Codification = 107
Ⅳ. Appreciation = 108
C. The Freedom of the Drafting Body to Codify or Develop the Law = 109
D. Functions of jus scriptum = 111
Ⅰ. Clarity and Certainty = 111
Ⅱ. The Sytematization of Law = 113
Ⅲ. Reform of Law = 113
4. METHODS OF CODIFICATION：CODES, RESOLUTIONS AND CONVENTIONS = 117
A. Introducton = 119
B. Code of Rules = 119
Ⅰ. Basis of Validity and Authority = 119
Ⅱ. Attributes = 120
Ⅲ. Types of Codes = 122
C. UN General Assembly Resolutions = 124
Ⅰ. Basis of Validity and Authority = 124
Ⅱ. Attributes = 127
Ⅲ. Resolutions and Declarations of Other Bodies = 129
D. Conventions = 129
Ⅰ. Bases of Validity = 129
a) Contractual Obligation = 129
b) State Practice = 131
c) Evidence of Customary Law = 132
Ⅱ. Political and Scientific Authority = 132
Ⅲ. Implications of the Legal Character of Conventions = 134
a) Independent Source of Obligation = 134
b) The Convention as a Homogeneous Whole = 135
c) Universality of, and Equality before, the Conventional Obligation = 136
d) Questions of Ascertainment = 139
Ⅳ. Special Types of Treaties, or Combinations with Other Methods = 141
E. Appreciation = 143
F. Embodiment of the Law of Treaties in a Convention = 146
5. EFFECTS OF A CONVENTION ON PRE-EXISTING CUSTOMARY INTERNATIONAL LAW = 149
A. Codificatory Conventional Rules = 151
Ⅰ. Some Views on the Matter = 151
Ⅱ. Criteria by which to Assess the Continuing Existence of Customary Law = 153
Ⅲ. In Particular Conventions with Quasi-Universal Membership = 156
Ⅳ. Implications = 158
B. Customary Rule son the Same Subject-Matter but with Different Content ; the expressio unius-Maxim = 160
C. Customary Rules on Subjects not Covered by the Convention = 161
D. Effects of Conventions with Few Parties, or not in Force = 163
Ⅰ. Reasons for Non-Acceptance = 163
Ⅱ. Detrimental Effects on Customary Law? = 164
6. GENERATION OF NEW CUSTOMARY INTERNATIONAL LAW = 167
A. Article 38 of the 1969 Vienna Convention on the Law of Treaties = 169
Ⅰ. Travaux pr ￦acutee paratoires = 169
Ⅱ. Interpretation of Article 38 = 171
a) Normative Quality? = 171
b) Functions of Article 38 = 172
B. Views of Courts and Authors = 173
C. Delimitations ; Articles 34-37 of the 1969 Vienna Convention = 175
D. Conditions for the Generation of New Customary International Law = 176
Ⅰ. New Rules of a "Norm-Creating", General Character = 176
a) Individual Rules = 177
b) New Rules = 177
c) General Rules = 177
d) Abstract Rules = 179
Ⅱ. Superseding Agreements and "Special Circumstances" = 180
Ⅲ. Reasons for the Generation of New Customary International Law = 181
E. The Process of the Generation of New Customary Rules = 181
Ⅰ. Codes, Resolutions, Conventions = 181
Ⅱ. General Conditions for the Formation of Customary Law = 182
Ⅲ. State Practice Coinciding with the Conventional Rule = 182
Ⅳ. Practice of Parties and Non-Parties = 183
Ⅴ. Questions of Time = 184
Ⅵ. Binding Nature = 186
F. Treaties as State Practice：Questions of Quasi-Legislative Effects and of a "Copyright" of Parties = 186
Ⅰ. Some Views on the Matter = 186
Ⅱ. Positive Functions of Convention Texts = 187
Ⅲ. Negative Functions of Convention Texts ; "Copyright" of Parties = 188
G. Bilateral Treaties = 189
H. Appreciation = 189
Ⅰ. Quasi-Legislative Functions = 189
Ⅱ. Comparison with Other Modes of the Creation of Customary Law = 190
Ⅲ. Position of Parties and Non-Parties = 191
7. MODIFICATION OF CONVENTIONAL RULES BY SUBSEQUENT CUSTOMARY LAW = 193
A. ILC Drafts and the 1969 Vienna Convention on the Law of Treaties = 195
Ⅰ. Article 68 para.(c) of the 1964 LEC Draft = 195
a) Legislative History = 195
b) Interpretation = 195
Ⅱ. Relevance of Article 31 subpara. 3(c) of the 1969 Vienna Convention = 199
Ⅲ. Relevance of Article 38 of the 1966 LEC Draft = 198
Ⅳ. Relevance of Article 42 and 54 of the 1969 Vienna Convention = 199
B. State Practice ; Views of Courts and Authors = 200
C. Grounds for Modification = 204
D. The Conflict between the Conventional and the Customary Rule = 205
Ⅰ. How Does the Conflict Arise? = 205
Ⅱ. Solution：Desuetude of the Conventional Rule ; Customary Law as the lex posterior = 206
Ⅲ. Conflict with a Declaratory Conventional Rule = 208
Ⅳ. Exceptions to a General Rule ; Special Customary Law and Special Treaties = 209
E. Origination and Formation of the New Customary Rule = 210
Ⅰ. Derogation from, or Breach of, the Conventional Rule = 210
Ⅱ. Modification through Interpretation and Adaptation = 213
F. Implications of the Customary Basis of the New Rule = 214
Ⅰ. Practice of Parties and Non-Parties = 214
Ⅱ. Consent of the Parties? = 215
Ⅲ. Opinio juris and the Intention to Depart from the Conventional Rule = 216
Ⅳ. Presumptions against Change ; the Difficulty of Ascertaining Modification = 217
G. Questions of Time = 218
H. Conclusions = 220
Ⅰ. Evaluation = 220
Ⅱ. Comparison with Other Means of Amendment = 221
8. IDENTIFICATION OF THE DECLARATORY QUALITY OF CONVENTIONAL RULES = 225
A. Preliminary Remarks = 227
Ⅰ. The Techniques of Identifying Declaratory Conventional Rules = 227
Ⅱ. When is Identification Necessary? = 227
Ⅲ. Relevance of Rule son Interpretation = 228
Ⅳ. The Value of Sweeping Statements = 229
B. The Strata of Materials = 230
Ⅰ. Pre-travaux pr ￦acutee paratoires Materials = 230
Ⅱ. Travaux pr ￦acutee paratoires = 230
Ⅲ. The Convention = 232
a) Convention Text = 232
b) Preambles = 236
c) Other Indicators = 236
Ⅳ. Subsequent State Practice = 238
C. The Techniques of Employing These Materials = 238
Ⅰ. Opinions of Courts, in particular the International Court of Justice (ICJ) = 238
Ⅱ. Doctrine ; Critique of the Prevalent Theory = 241
D. Evaluatin = 244
Ⅰ. Necessity to Consider All Elements ; Order of Examination = 244
Ⅱ. Multiple Inconsistencies, Paucity of Results = 246
Ⅲ. Complete Identity of the Written and Unwritten Rule? = 247
9. EFFECTS OF THE DECLARATORY NATURE OF CONVENTIONAL RULES = 249
A. Effects Before the Entry into Force of the Convention = 251
Ⅰ. Relevance of Articles 4 and 28 of the 1969 Vienna Convention = 251
Ⅱ. Notion = 253
B. Reservations = 254
Ⅰ. Reservations to Declaratory Rules = 254
a) Admissibility of Reservations = 254
b) Reservation Clauses = 254
c) Applicable Law = 257
d) Effects of Reservations upon Underlying Customary Law = 261
Ⅱ. Reservations to Non-Declaratory Rules = 261
Ⅲ. Evaluation = 263
C. Influence of Customary and Conventional Rules on the Interpretation and Identification of One Another = 264
Ⅰ. Relevance of Article 31 subpara. 3(c) of the 1969 Vienna Convention = 264
Ⅱ. Functions of the Customary Rule for the Interpretation of the Conventional Rule = 265
Ⅲ. Functions of th Conventional Rule for the Customary Rule = 267
D. Subsequent Changes in the Conventional R ￦acutee gime = 269
Ⅰ. Framework of the 1969 Vienna Convention = 269
a) Relevance of Articles 43 and 60 para. 5 = 269
b) Relevance of Article 56 = 270
Ⅱ. Effects of the Invalidity, Termination or Denunciation of a Convention, or of the Suspension of its Operation = 271
Ⅲ. Amendment of Conventional Rules = 274
10. CONCLUSIONS = 275
A. Degree of Recognition of Customary Law in the State Community = 277
B. Codification and Progressive Development ; Declaratory and Non-Declaratory Rules = 278
C. Conservative Impact of jus scriptum on Customary Law = 280
D. Dynamic Impact of Customary Law on jus scriptum = 281
E. Individualistic and Communal Interests of States = 284
F. Customary Law and Treaties as Sources of Law = 286
G. Identification o Customary Law = 288
H. Customary Law and the Present International Community = 289
I. Codification of the Interplay of Sources? = 290
BIBLIOGRAPHY = 293
ABLE OF TREATIES, STATUTES AND TRAVAUX PR ￦acuteE PARATOIRES = 325
TABLE OF CASES = 329
INDEX = 333
